Loudness normalization

Audio gets delivered to us at different volume levels.

We use loudness normalization to balance soft and loud songs, creating a more balanced uniform experience.

Note: The web player and 3rd-party devices (e.g. speakers and TVs) don’t use loudness normalization.

How we adjust loudness

We adjust tracks to -14 dB LUFS, according to the ITU 1770 (International Telecommunication Union) standard.

• We normalize an entire album at the same time, so gain compensation doesn’t change between tracks. This means the softer tracks are as soft as you intend them to be.
• We adjust individual tracks when shuffling an album or listening to tracks from multiple albums (e.g. listening to a playlist).

Positive or negative gain compensation gets applied to a track while it’s playing.

• Negative gain is applied to louder masters so the loudness level is -14 dB LUFS. This lowers the volume in comparison to the master - no additional distortion occurs.
• Positive gain is applied to softer masters so the loudness level is -14 dB LUFS. We consider the headroom of the track, and leave 1 dB headroom for lossy encodings to preserve audio quality.
  Example: If a track loudness level is -20 dB LUFS, and its True Peak maximum is -5 dB FS, we only lift the track up to -16 dB LUFS.

Premium listeners can also choose volume normalization levels in the app settings to compensate for a noisy or quiet environment

• Loud: -11dB LUFS
  Note: We set this level regardless of maximum True Peak. We apply a limiter to prevent distortion and clipping in soft dynamic tracks. The limiter’s set to engage at -1 dB (sample values), with a 5 ms attack time and a 100 ms decay time.
• Normal: -14dB LUFS
• Quiet: -19dB LUFS

Mastering tips

Loudness normalization means we don’t always play your track at the level it’s mastered.

• Target the loudness level of your master at -14dB integrated LUFS and keep it below -1dB TP (True Peak) max. This is best for lossy formats (Ogg/Vorbis and AAC) and makes sure no extra distortion’s introduced in the transcoding process.
• If your master’s louder than -14dB integrated LUFS, make sure it stays below -2dB TP (True Peak) to avoid extra distortion. This is because louder tracks are more susceptible to extra distortion in the transcoding process.